Exemplary embodiments of the present invention relate to an ejection device for separating an ejectable flight data recorder, for example, from an aircraft cell.
In conventional ejectable flight data recorders explosive cartridges, explosive screw bolts or squibs are used in order to separate the connection between the ejectable part and the ejection device of the flight data recorder system. This method is extremely operationally safe and reliable because very few electrical, mechanical and chemical components are involved in functionality.
Handling the explosive substances required for this purpose has been burdened in the last ten years with stringent conditions with regard to dispatch, storage and installation. This leads to high costs for the use or exchange of the respective components and to a decrease in readiness of aircraft manufacturers or aircraft operators to integrate such parts in or on an aircraft.
GB 1,318,197 describes an ejection device for a flight data recorder in which the flight data recorder is ejected by means of a gas pressure generator. The gas pressure generator acts upon a pressure chamber, the internal pressure of which, in turn, acts directly upon the housing of the flight data recorder. A further ejection device operated by gas pressure is disclosed in German Patent Document DE 198 48 801 C2.
German Patent Document DE 196 09 501 C2 uses a catapult device with an explosive charge in order to eject the flight data recorder, while a rocket is proposed for this purpose in U.S. Pat. No. 3,140,847.
Exemplary embodiments of the present invention are direct to an ejection device for a flight data recorder that places no demands in terms of dispatch, storage and installation upon specially trained personnel for the handling of explosive substances:                No or only minor restrictions in the dispatch of the parts;        the parts are to be transportable in large quantities, unprotected, in a crate, without special “separation instructions”, by regular mail services (for example, UPS);        the parts are to be depositable in a store without special safety requirements;        the installation of the parts in the ejection device is to be possible by service personnel requiring no special permit for handling explosive substances.        
The device according to the invention fulfills all the requirements described above because                no explosive substances of any kind are used,        all effects of unintentional triggering have no harmful effects (such as, for example, mechanical bolts/screws shooting out or the action of heat) upon people or objects located outside the device,        the energy required for separating an ejectable flight data recorder is, in the event of a fault, absorbed and nullified inside the device or diverted harmlessly.        
Furthermore, the device according to the invention is designed in such a way that even serious mechanical effects caused by accidents or improper use cannot cause the ejection device to be functionally impaired or damaged.
The device according to the invention can be produced cost-effectively and its purchase price does not deviate appreciably from that of a conventional explosive cartridge.